Love these apms but tooo expensive...is DIY possible? Is there a place selling complete kit?
I remember someone told me Pass Labs actually has kit for sale, but I have checked their site and can't finad anything.
Sorry if this question was asked before, I am new member here. Thanks!

(if x-250/x-350 is not available, is there any other option for me? I'd like to DIY a true class A, 50-100w apm, preffer full kit...I head x-250/x-350 is true class A when output is less than 50w, right?)

There isn't a kit for any of the X amps. As Hans B noted, Petter did a nice job of reverse engineering the circuit to produce a 100W version. Other variations are possible.
The X amplifiers run class AB, which means that they are class A up to some arbitrary point (depending on where the bias is set), then operate in class B. There was a thread where folks were speculating on the level at which the transition occurred, but I don't remember what the final figure was. You're using the phrase 'true class A' to describe the circuit you want to build, but if you're speaking in terms of an X amplifier, it's not actually class A.
I gather that you're new to DIY. If you're serious about building a class A amplifier, I think you'll find the Aleph amplifiers to be a lot easier to deal with. Quite a few people have been down that path. As far as I know, Mark Finnis and I were among the first to go that route. I've got a thread here on building the Aleph 2, and Mark has a web page. I think he built a 4. If you're interested in pursuing the Alephs, go to www.passlabs.com, go to Products, then to the bottom of the page. There's a link there to the full service manuals (including schematics).
If you want a class AB amp, particularly a large amp, there aren't too many places you can go. I think there's one on the ESP pages, and certainly you should at least look over Anthony Holton's stuff, as I know he's got some monster amps. Roam the links in the project amp area listed here on the DIY site.

If you want to learn to build amplifiers, and you are a first timer, i
strongly reccomend that you start with the Zen articles on PassDIY.
Don't get hung up on the number of watts, or the class
of amplification, etc. Building something that works, and sounds
good is a great feeling.

What you can learn from those articles and the huge amount of
information contained in this forum - you have a great chance of
success. All i can say is that if i could do it - so can you!!

In order to build a true x-amp you need to get the service manual. I have read of one account of a man by the name of David Smith ordering a service manual for his X350 on www.audioreview. He says ďI contacted the factory and obtained a service manual.Ē I wonder if Mr. Pass would send me a service manual for some type of fee.

I would be uncomfortable building an amp from Petters circuit. It may be 99.99% the same as the true x-amp, however one inappropriate resistor value will take away from the sound of the amp. Petter gave little info on the sound of the amp and I donít know of anyone else who has built his circuit. After about 10 good reviews I would opt to build it. Everyone seems caught up by XA madness. I canít think why. A good size XA amp uses up so much power.

Uli has also built an X-Amp from his own circuit. Itís a little more stable and better documented compared to Petters circuit. Just look up the ďnormal X-AmpĒ thread.

Iím also donít know if the lower bias amps like the x5 with an idle dissipation of 40 watts per channel sound as good as the bigger higher idle dissipation amps like the x350.

Iím driving my self mad trying to pick which amp will suit my needs best. My current choice is Anthony E Holtonís N-channel Amplifier; however I may change my mind on that. It packs a little bit more punch on the bottom then the Aleph and the dissipation is only 46watts.